38? 
Tin .. 
iron plates. He cannot depend on the iron plates manu- 
factured in this country, nor indeed on any that are not 
manufactured under his own eye, I make these remarks 
because I do not know a more tempting speculation than 
the manufacture of tinned iron plates in this country ; nor 
any, where a person who does not sit down to calculate 
carefully all the requisites of such a manufacture here , 
may be more easily deceived. 
Making of tinfoil The tin is melted into ingots, and 
then hammered on a smooth iron plate. I do not know 
whether rolling has been tried. All the tin foil I have 
seen, appears to contain an admixture of lead. Tin foil 
is used for silvering looking glasses, and for coating elec- 
trical jars, In the latter case it is merely fastened on the 
glass with paste. But M. Sage’s paper which I am 
about to give, will furnish information on this subject. 
To coat looking glasses with Tinfoil and Mercury ; com- 
monly called the Silvering of looking glasses . 
In order to go completely forward, you must be pre- 
pared with the following articles, viz. 
First, A square marble slab, or smooth stone, well po- 
lished, and ground exceedingly true, the larger the better, 
with a frame round it, or a groove cut in its edges, to 
keep the superfluous mercury from running off. Se- 
condly, Lead weights covered with cloth, to keep them 
from scratching the glass, from one pound weight to 
twelve pounds each, according to the size of the glass 
which is laid down. Thirdly, Rolls of tinfoil. Fourth- 
ly, Mercury or quicksilver, with which you must be well 
provided ; then proceed as follows. 
Cut the tinfoil a little larger than the glass every way. 
aud lay it flat upon the stone, and with a straight piece of 
hard wood, about three inches long, stroke it every way, 
Vol. Ill 3 B ^ 
